Merge llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and openmp
llvmorg-10.0.0-0-gd32170dbd5b (aka 10.0.0 release), and a number of
follow-ups.

MFC r356479 (by bdragon):

[PowerPC] Fix libllvmminimal build when building from powerpc64 ELFv1.

When bootstrapping on powerpc64 ELFv1, it is necessary to use binutils
ld.bfd from ports for the bootstrap, as this is the only modern linker for
ELFv1 host tools.

As binutils ld.bfd is rather strict in its handling of undefined symbols,
it is necessary to pull in Support/Atomic.cpp to avoid an undefined symbol.

Reviewed by: dim, emaste
Sponsored by: Tag1 Consulting, Inc.
Differential Revision: https://reviews.freebsd.org/D23072

MFC r356930:

Add more Subversion mergeinfo bootstrap information, to hopefully
increase the probability of merging in vendor changes.

MFC r358408 (by brooks):

Merge commit 7214f7a79 from llvm git (by Sam Elliott):

[RISCV] Lower llvm.trap and llvm.debugtrap

Summary:
Until this commit, these have lowered to a call to abort().

`llvm.trap()` now lowers to `unimp`, which should trap on all systems.

`llvm.debugtrap()` now lowers to `ebreak`, which is exactly what this
instruction is for.

Reviewers: asb, luismarques

Reviewed By: asb

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69390

This fixes miscompilation resulting in linking failures with
INVARIANTS disabled.

Reviewed by: dim
Differential Revision: https://reviews.freebsd.org/D23857

MFC r358851:

Merge llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and openmp
10.0.0-rc3 c290cb61fdc.

Release notes for llvm, clang, lld and libc++ 10.0.0 will become
available here:

https://releases.llvm.org/10.0.0/docs/ReleaseNotes.html
https://releases.llvm.org/10.0.0/tools/clang/docs/ReleaseNotes.html
https://releases.llvm.org/10.0.0/tools/lld/docs/ReleaseNotes.html
https://releases.llvm.org/10.0.0/projects/libcxx/docs/ReleaseNotes.html

PR: 244251

MFC r358854:

Add one additional file to libllvmminimal, to help the ppc64 bootstrap.

Reported by: bdragon
PR: 244251

MFC r358857:

Move another file in libllvm from sources required for world, to sources
required for bootstrap, as the PowerPC builds need this.

Reported by: bdragon
PR: 244251

MFC r359082:

Merge llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and openmp
llvmorg-10.0.0-rc4-5-g52c365aa9ca. The actual release should follow Real
Soon Now.

PR: 244251

MFC r359084:

Merge commit 00925aadb from llvm git (by Fangrui Song):

[ELF][PPC32] Fix canonical PLTs when the order does not match the PLT order

Reviewed By: Bdragon28

Differential Revision: https://reviews.llvm.org/D75394

This is needed to fix miscompiled canonical PLTs on ppc32/lld10.

Requested by: bdragon
Differential Revision: https://reviews.freebsd.org/D24109

MFC r359085:

Merge commit 315f8a55f from llvm git (by Fangrui Song):

[ELF][PPC32] Don't report "relocation refers to a discarded section"
for .got2

Similar to D63182 [ELF][PPC64] Don't report "relocation refers to a
discarded section" for .toc

Reviewed By: Bdragon28

Differential Revision: https://reviews.llvm.org/D75419

This is needed to fix compile errors when building for ppc32/lld10.

Requested by: bdragon
Differential Revision: https://reviews.freebsd.org/D24110

MFC r359086:

Merge commit b8ebc11f0 from llvm git (by Sanjay Patel):

[EarlyCSE] avoid crashing when detecting min/max/abs patterns (PR41083)

As discussed in PR41083:
https://bugs.llvm.org/show_bug.cgi?id=41083
...we can assert/crash in EarlyCSE using the current hashing scheme
and instructions with flags.

ValueTracking's matchSelectPattern() may rely on overflow (nsw, etc)
or other flags when detecting patterns such as min/max/abs composed
of compare+select. But the value numbering / hashing mechanism used
by EarlyCSE intersects those flags to allow more CSE.

Several alternatives to solve this are discussed in the bug report.
This patch avoids the issue by doing simple matching of min/max/abs
patterns that never requires instruction flags. We give up some CSE
power because of that, but that is not expected to result in much
actual performance difference because InstCombine will canonicalize
these patterns when possible. It even has this comment for abs/nabs:

/// Canonicalize all these variants to 1 pattern.
/// This makes CSE more likely.

(And this patch adds PhaseOrdering tests to verify that the expected
transforms are still happening in the standard optimization
pipelines.

I left this code to use ValueTracking's "flavor" enum values, so we
don't have to change the callers' code. If we decide to go back to
using the ValueTracking call (by changing the hashing algorithm
instead), it should be obvious how to replace this chunk.

Differential Revision: https://reviews.llvm.org/D74285

This fixes an assertion when building the math/gsl port on PowerPC64.

Requested by: pkubja

MFC r359087:

Merge commit 585a3cc31 from llvm git (by me):

Fix -Wdeprecated-copy-dtor and -Wdeprecated-dynamic-exception-spec
warnings.

Summary:
The former are like:

libcxx/include/typeinfo:322:11: warning: definition of implicit copy
constructor for 'bad_cast' is deprecated because it has a
user-declared destructor [-Wdeprecated-copy-dtor]
virtual ~bad_cast() _NOEXCEPT;
^
libcxx/include/typeinfo:344:11: note: in implicit copy constructor
for 'std::bad_cast' first required here
throw bad_cast();
^

Fix these by adding an explicitly defaulted copy constructor.

The latter are like:

libcxx/include/codecvt:105:37: warning: dynamic exception
specifications are deprecated [-Wdeprecated-dynamic-exception-spec]
virtual int do_encoding() const throw();
^~~~~~~

Fix these by using the _NOEXCEPT macro instead.

Reviewers: EricWF, mclow.lists, ldionne, #libc

Reviewed By: EricWF, #libc

Subscribers: dexonsmith, libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D76150

This is because we use -Wsystem-headers during buildworld, and the two
warnings above are now triggered by default with clang 10, preventing
most C++ code from compiling without NO_WERROR.

Requested by: brooks
Differential Revision: https://reviews.freebsd.org/D24049

MFC r359333:

Merge commit f0990e104 from llvm git (by Justin Hibbits):

[PowerPC]: e500 target can't use lwsync, use msync instead

The e500 core has a silicon bug that triggers an illegal instruction
program trap on any sync other than msync. Other cores will typically
ignore illegal sync types, and the documentation even implies that
the 'illegal' bits are ignored.

Address this hardware deficiency by only using msync, like the PPC440.

Differential Revision: https://reviews.llvm.org/D76614

Requested by: jhibbits

MFC r359334:

Merge commit 459e8e948 from llvm git (by Justin Hibbits):

[PowerPC]: Don't allow r0 as a target for LD_GOT_TPREL_L/32

Summary:
The linker is free to relax this (relocation R_PPC_GOT_TPREL16)
against R_PPC_TLS, if it sees fit (initial exec to local exec). If r0
is used, this can generate execution-invalid code (converts to 'addi
%rX, %r0, FOO, which translates in PPC-lingo to li %rX, FOO). Forbid
this instead.

This fixes static binaries using locales on FreeBSD/powerpc (tested
on FreeBSD/powerpcspe).

Reviewed By: nemanjai
Differential Revision: https://reviews.llvm.org/D76662

Requested by: jhibbits

MFC r359338:

Merge llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and openmp
llvmorg-10.0.0-0-gd32170dbd5b (aka 10.0.0 release).

PR: 244251

MFC r359506 (by emaste):

lldb: stop excluding bindings/ subdir

With liblua in the tree we should be able to enable lldb's lua
scripting. We'll need the files in bindings/, so start by allowing them
to come in with the next import.

Approved by: dim
Sponsored by: The FreeBSD Foundation

MFC r359578:

Merge once more from ^/vendor/llvm-project/release-10.x, to get the
lldb/bindings directory, which will be used to provide lua bindings for
lldb.

Requested by: emaste

MFC r359826:

Merge commit 30588a739 from llvm git (by Erich Keane):

Make target features check work with ctor and dtor-

The problem was reported in PR45468, applying target features to an
always_inline constructor/destructor runs afoul of GlobalDecl
construction assert when checking for target-feature compatibility.

The core problem is fixed by using the version of the check that
takes a FunctionDecl rather than the GlobalDecl. However, while
writing the test, I discovered that source locations weren't properly
set for this check on ctors/dtors. This patch also fixes constructors
and CALLED destructors.

Unfortunately, it doesn't seem too possible to get a meaningful
source location for a 'cleanup' destructor, so those are still
'frontend' level errors unfortunately. A fixme was added to the test
to cover that situation.

This should fix 'Assertion failed: (!isa<CXXConstructorDecl>(D) && "Use
other ctor with ctor decls!"), function Init, file
/usr/src/contrib/llvm-project/clang/include/clang/AST/GlobalDecl.h, line
45' when compiling the security/botan2 port.

PR: 245550

MFC r359981:

Revert commit a9ad65a2b from llvm git (by Nemanja Ivanovic):

[PowerPC] Change default for unaligned FP access for older subtargets

This is a fix for https://bugs.llvm.org/show_bug.cgi?id=40554

Some CPU's trap to the kernel on unaligned floating point access and
there are kernels that do not handle the interrupt. The program then
fails with a SIGBUS according to the PR. This just switches the
default for unaligned access to only allow it on recent server CPUs
that are known to allow this.

Differential revision: https://reviews.llvm.org/D71954

This upstream commit causes a compiler hang when building certain ports
(e.g. security/nss, multimedia/x264) for powerpc64. The hang has been
reported in https://bugs.llvm.org/show_bug.cgi?id=45186, but in the mean
time it is more convenient to revert the commit.

Requested by: jhibbits

MFC r359994:

Revert commit b6cf400aa fro llvm git (by Nemanja Ivanovic):

Fix bots after a9ad65a2b34f

In the last commit, I neglected to initialize the new subtarget
feature I added which caused failures on a few bots. This should fix
that.

This unbreaks the build after r359981, which reverted upstream commit
a9ad65a2b34f.

Reported by: jhibbits (and jenkins :)

MFC r360129:

Merge commit ce5173c0e from llvm git (by Reid Kleckner):

Use FinishThunk to finish musttail thunks

FinishThunk, and the invariant of setting and then unsetting
CurCodeDecl, was added in 7f416cc42638 (2015). The invariant didn't
exist when I added this musttail codepath in ab2090d10765 (2014).
Recently in 28328c3771, I started using this codepath on non-Windows
platforms, and users reported problems during release testing
(PR44987).

The issue was already present for users of EH on i686-windows-msvc,
so I added a test for that case as well.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D76444

This should fix 'Assertion failed: (!empty() && "popping exception stack
when not empty"), function popTerminate, file
/usr/src/contrib/llvm-project/clang/lib/CodeGen/CGCleanup.h, line 583'
when building the net-p2p/libtorrent-rasterbar

PR: 244830
Reported by: jbeich, yuri

MFC r360134:

Merge commit 64b31d96d from llvm git (by Nemanja Ivanovic):

[PowerPC] Do not attempt to reuse load for 64-bit FP_TO_UINT without
FPCVT

We call the function that attempts to reuse the conversion without
checking whether the target matches the constraints that the callee
expects. This patch adds the check prior to the call.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=43976

Differential revision: https://reviews.llvm.org/D77564

This should fix 'Assertion failed: ((Op.getOpcode() == ISD::FP_TO_SINT
|| Subtarget.hasFPCVT()) && "i64 FP_TO_UINT is supported only with
FPCVT"), function LowerFP_TO_INTForReuse, file
/usr/src/contrib/llvm/lib/Target/PowerPC/PPCISelLowering.cpp, line 7276'
when building the devel/libslang2 port (and a few others) for PowerPC64.

Requested by: pkubaj

MFC r360350:

Tentatively apply https://reviews.llvm.org/D78877 (by Dave Green):

[ARM] Only produce qadd8b under hasV6Ops

When compiling for a arm5te cpu from clang, the +dsp attribute is
set. This meant we could try and generate qadd8 instructions where we
would end up having no pattern. I've changed the condition here to be
hasV6Ops && hasDSP, which is what other parts of ARMISelLowering seem
to use for similar instructions.

Fixed PR45677.

This fixes "fatal error: error in backend: Cannot select: t37: i32 =
ARMISD::QADD8b t43, t44" when compiling sys/dev/sound/pcm/feeder_mixer.c
for armv5. For some reason we do not encounter this on head, but this
error popped up while building universes for stable/12.

MFC r360697:

In r358396 I merged llvm upstream commit 2e24219d3, which fixed "error:
unsupported relocation on symbol" when assembling arm 'adr' pseudo
instructions. However, the upstream commit did not take big-endian arm
into account.

Applying the same changes to the big-endian handling is straightforward,
thanks to Andrew Turner and Peter Smith for the hint. This will also be
submitted upstream.

Merge llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and openmp
8.0.0 final release r356365.

MFC r306265 (by emaste):

Force LLVM_LIBUNWIND off if we don't have a C++11 compiler

Tested by: bde
Differential Revision: https://reviews.freebsd.org/D7746

MFC r308100 (by emaste):

compile libunwind c source with -fexceptions

When an exception is thrown the unwinder must unwind its own C source
(starting with _Unwind_RaiseException in UnwindLevel1.c), so it needs to
be built with unwinding data.

MFC r324998 (by bdrewery):

Prefix {TARGET,BUILD}_TRIPLE with LLVM_ to avoid Makefile.inc1 collision.

The Makefile.inc1 TARGET_TRIPLE is for specifying which -target is used
during the build of world.

Reviewed by: dim, imp
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D12792

MFC r329093 (by emaste):

Promote llvm-cov to a standalone option

Introduce WITH_/WITHOUT_LLVM_COV to match GCC's WITH_/WITHOUT_GCOV.
It is intended to provide a superset of the interface and functionality
of gcov.

It is enabled by default when building Clang, similarly to gcov and GCC.

This change moves one file in libllvm to be compiled unconditionally.
Previously it was included only when WITH_CLANG_EXTRAS was set, but the
complexity of a new special case for (CLANG_EXTRAS | LLVM_COV) is not
worth avoiding a tiny increase in build time.

Reviewed by: dim, imp
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D142645

MFC r331244 (by jhb):

Add support for MIPS to LLVM's libunwind.

This is originally based on a patch from David Chisnall for soft-float
N64 but has since been updated to support O32, N32, and hard-float ABIs.
The soft-float O32, N32, and N64 support has been committed upstream.
The hard-float changes are still in review upstream.

Enable LLVM_LIBUNWIND on mips when building with a suitable (C+11-capable)
toolchain. This has been tested with external GCC for all ABIs and
O32 and N64 with clang.

Reviewed by: emaste
Obtained from: CheriBSD (original N64 patch)
Sponsored by: DARPA / AFRL
Differential Revision: https://reviews.freebsd.org/D14701

MFC r336691 (by emaste):

llvm: remove __FreeBSD_version conditionals

All supported FreeBSD build host versions have backtrace.h, so we can
just eliminate that test. For futimes() we can test the compiler's
built-in __FreeBSD__ major version rather than relying on including
osreldate.h. This should reduce the frequency with which Clang gets
rebuilt when building world.

Reviewed by: dim
Sponsored by: The FreeBSD Foundation

MFC r337379 (by andrew):

Default to armv5te in LINT on arm. This should fix building LINT there.

MFC r337552:

Add optional LLVM BPF target support

BPF (eBPF) is an independent instruction set architecture which is
introduced in Linux a few years ago. Originally, eBPF execute
environment was only inside Linux kernel. However, recent years there
are some user space implementation (https://github.com/iovisor/ubpf,
https://doc.dpdk.org/guides/prog_guide/bpf_lib.html) and kernel space
implementation for FreeBSD is going on
(https://github.com/YutaroHayakawa/generic-ebpf).

The BPF target support can be enabled using WITH_LLVM_TARGET_BPF, as it
is not built by default.

Submitted by: Yutaro Hayakawa <yhayakawa3720@gmail.com>
Reviewed by: dim, bdrewery
Differential Revision: https://reviews.freebsd.org/D16033

MFC r337585:

In r308100, an explicit -fexceptions flag was added for the C sources
from LLVM's libunwind, which end up in libgcc_eh.a and libgcc_s.so.
This is because the unwinder needs the unwinder data for its own
functions.

However, for the C++ sources in libunwind, -fexceptions is already the
default, and this can have the side effect of generating a reference to
__gxx_personality_v0, the so-called personality function, which is
normally provided by the C++ ABI library (libcxxrt or libsupc++).

If the reference ends up in the eventual libgcc_s.so, linking any
non-C++ programs against it will fail with "undefined reference to
`__gxx_personality_v0'".

Note that at high optimization levels, the reference is usually
optimized away, which is why we have never noticed this problem before.

With clang 7.0.0 though, higher optimization levels don't help anymore,
since the addition of address-significance tables [1] in
<https://reviews.llvm.org/rL337339>. Effectively, this always causes a
reference to __gxx_personality_v0.

After discussion with the upstream author of that change, it turns out
that we should compile libunwind sources with the -fno-exceptions
-funwind-tables flags instead. This ensures unwind tables are
generated, but no references to any personality functions are emitted.

[1] https://lists.llvm.org/pipermail/llvm-dev/2018-May/123514.html

Reported by: jbeich
PR: 230399

MFC r340287 (by emaste):

Consolidate gcov entries in OptionalObsoleteFiles

Sponsored by: The FreeBSD Foundation

MFC r340289 (by emaste):

llvm-cov: also install as gcov (if GNU gcov is disabled)

llvm-cov provides a gcov-compatible interface when invoked as gcov.

Reviewed by: dim, markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D17923

MFC r340296 (by emaste):

Move llvm-profdata build into MK_LLVM_COV block

llvm-profdata is used with llvm-cov for code coverage (although llvm-cov
can also operate independently in a gcov-compatible mode).
Although llvm-profdata can be used independently of llvm-cov it makes
sense to group these under one option.

Also handle these in OptionalObsoleteFiles.inc while here.

Sponsored by: The FreeBSD Foundation

MFC r340300 (by emaste):

libllvm: Move SampleProfWriter to SRCS_MIN

It is required by llvm-profdata, now built by default under the
LLVM_COV knob. The additional complexity that would come from avoiding
building it if CLANG_EXTRAS and LLVM_COV are both disabled is not worth
the small savings in build time.

Sponsored by: The FreeBSD Foundation

MFC r340972 (by emaste):

llvm-objdump: initial man page

Based on llvm-objdump's online documentation and usage information.
This serves as a starting point; additional detail and cleanup still
required.

Also being submitted upstream in LLVM review D54864. I expect to use
this bespoke copy while we have LLVM 6.0 or 7.0 in FreeBSD; when we
update to LLVM 8.0 it should be upstream and we will switch to it.

PR: 233437
Reviewed by: bcr (man formatting)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D18309

MFC r340973 (by emaste):

llvm-objdump.1: remove invalid options

Some options appear in llvm-objdump's usage information as a side effect
of its option parsing implementation and are not actually llvm-objdump
options. Reported in LLVM review https://reviews.llvm.org/D54864.

Reported by: Fangrui Song
Sponsored by: The FreeBSD Foundation

MFC r340975 (by emaste):

llvm-objdump.1: fix igor / mandoc -Tlint warnings

Accidentally omitted from r340972.

MFC r341055 (by emaste):

llvm-objdump.1: remove more unintentional options

Some options come from static constructors in LLVM libraries and are
automatically added to llvm's usage output. They're not really supposed
to be llvm-objdump options.

Reported by: Fangrui Song in LLVM review D54864
Sponsored by: The FreeBSD Foundation

MFC r344779:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
the upstream release_80 branch r355313 (effectively, 8.0.0 rc3). The
release will follow very soon, but no more functional changes are
expected.

Release notes for llvm, clang and lld 8.0.0 will soon be available here:
<https://releases.llvm.org/8.0.0/docs/ReleaseNotes.html>
<https://releases.llvm.org/8.0.0/tools/clang/docs/ReleaseNotes.html>
<https://releases.llvm.org/8.0.0/tools/lld/docs/ReleaseNotes.html>

PR: 236062
Relnotes: yes

MFC r344798 (by emaste):

libllvm: promote WithColor and xxhash to SRCS_MIN

The armv6 build failed in CI due to missing symbols (from these two
source files) in the bootstrap Clang.

This affected only armv6 because other Clang-using archs are using LLD
as the bootstrap linker, and thus include SRCS_MIW via LLD_BOOTSTRAP.

Reported by: CI, via lwhsu
Sponsored by: The FreeBSD Foundation

MFC r344825:

Add a few missed files to the MK_LLVM_TARGET_BPF=yes case, otherwise
clang and various other executables will fail to link with undefined
symbols.

Reported by: O. Hartmann <ohartmann@walstatt.org>

MFC r344852:

Put in a temporary workaround for what is likely a gcc 6 bug (it does
not occur with gcc 7 or later). This should prevent the following error
from breaking the head-amd64-gcc CI builds:

In file included from /workspace/src/contrib/llvm/tools/lldb/source/API/SBMemoryRegionInfo.cpp:14:0:
/workspace/src/contrib/llvm/tools/lldb/include/lldb/Target/MemoryRegionInfo.h:128:54: error: 'template<class _InputIterator> lldb_private::MemoryRegionInfos::MemoryRegionInfos(_InputIterator, _InputIterator, const allocator_type&)' inherited from 'std::__1::vector<lldb_private::MemoryRegionInfo>'
using std::vector<lldb_private::MemoryRegionInfo>::vector;
^~~~~~
/workspace/src/contrib/llvm/tools/lldb/include/lldb/Target/MemoryRegionInfo.h:128:54: error: conflicts with version inherited from 'std::__1::vector<lldb_private::MemoryRegionInfo>'

Reported by: CI

MFC r344896:

Pull in r354937 from upstream clang trunk (by Jörg Sonnenberger):

Fix inline assembler constraint validation

The current constraint logic is both too lax and too strict. It fails
for input outside the [INT_MIN..INT_MAX] range, but it also
implicitly accepts 0 as value when it should not. Adjust logic to
handle both correctly.

Differential Revision: https://reviews.llvm.org/D58649

Pull in r355491 from upstream clang trunk (by Hans Wennborg):

Inline asm constraints: allow ICE-like pointers for the "n"
constraint (PR40890)

Apparently GCC allows this, and there's code relying on it (see bug).

The idea is to allow expression that would have been allowed if they
were cast to int. So I based the code on how such a cast would be
done (the CK_PointerToIntegral case in
IntExprEvaluator::VisitCastExpr()).

Differential Revision: https://reviews.llvm.org/D58821

These should fix assertions and errors when using the inline assembly
"n" constraint in certain ways.

In case of devel/valgrind, a pointer was used as the input for the
constraint, which lead to "Assertion failed: (isInt() && "Invalid
accessor"), function getInt".

In case of math/secp256k1, a very large integer value was used as input
for the constraint, which lead to "error: value '4624529908474429119'
out of range for constraint 'n'".

PR: 236216, 236194

MFC r344951:

Merge llvm, clang, compiler-rt, libc++, lld, and lldb release_80 branch
r355677 (effectively, 8.0.0 rc4), resolve conflicts, and bump version
numbers.

PR: 236062

MFC r345018:

Merge LLVM libunwind trunk r351319, from just before upstream's
release_80 branch point. Afterwards, we will merge the rest of the
changes in the actual release_80 branch.

PR: 236062

MFC r345019:

Merge LLVM libunwind release_80 branch r355677 (effectively, 8.0.0 rc4).

PR: 236062

MFC r345021:

Pull in r355854 from upstream llvm trunk (by Jonas Paulsson):

[RegAlloc] Avoid compile time regression with multiple copy hints.

As a fix for https://bugs.llvm.org/show_bug.cgi?id=40986 ("excessive
compile time building opencollada"), this patch makes sure that no
phys reg is hinted more than once from getRegAllocationHints().

This handles the case were many virtual registers are assigned to the
same physreg. The previous compile time fix (r343686) in
weightCalcHelper() only made sure that physical/virtual registers are
passed no more than once to addRegAllocationHint().

Review: Dimitry Andric, Quentin Colombet
https://reviews.llvm.org/D59201

This should fix a hang when compiling certain generated .cpp files in
the graphics/opencollada port.

PR: 236313

MFC r345068 (by jhb):

Move libunwind out of contrib/llvm/projects.

Move LLVM's libunwind to its own contrib/ directory similar to other
runtime libraries like libc++ and libcxxrt.

Reviewed by: dim, emaste
Differential Revision: https://reviews.freebsd.org/D19534

MFC r345073:

Revert r308867 (which was originally committed in the clang390-import
project branch):

Work around LLVM PR30879, which is about a bad interaction between
X86 Call Frame Optimization on i386 and libunwind, by disallowing the
optimization for i386-freebsd12.

This should fix some instances of broken exception handling when
frame pointers are omitted, in particular some unittests run during
the build of editors/libreoffice.

This hack will be removed as soon as upstream has implemented a more
permanent fix for this problem.

And indeed, after r345018 and r345019, which updated LLVM libunwind to
the most recent version, the above workaround is no longer needed. The
upstream commit which fixed this is:

https://llvm.org/viewvc/llvm-project?view=revision&revision=292723

Specifically, 32 bit (i386-freebsd) executables optimized with omitted
frame pointers and Call Frame Optimization should now behave correctly
when a C++ exception is thrown, and the stack is unwound.

Upstream PR: https://llvm.org/bugs/show_bug.cgi?id=30879
PR: 236062

MFC r345152:

Merge llvm, clang, compiler-rt, libc++, libunwind, lld, and lldb
release_80 branch r356034 (effectively, 8.0.0 rc5), resolve conflicts,
and bump version numbers.

PR: 236062

MFC r345231:

Add LLVM openmp trunk r351319 (just before the release_80 branch point)
to contrib/llvm. This is not yet connected to the build, the glue for
that will come in a follow-up commit.

PR: 236062

MFC r345232:

Bootstrap svn:mergeinfo on contrib/openmp.

PR: 236062

MFC r345233:

Merge openmp release_80 branch r356034 (effectively, 8.0.0 rc5).

PR: 236062

MFC r345234:

Add openmp __kmp_gettid() wrapper, using pthread_getthreadid_np(3).
This has also been submitted upstream.

PR: 236062

MFC r345283:

Enable building libomp.so for 32-bit x86. This is done by selectively
enabling the functions that save and restore MXCSR, since access to this
register requires SSE support.

Note that you may run into other issues with OpenMP on i386, since this
*not* yet supported upstream, and certainly not extensively tested.

PR: 236062, 236582

MFC r345345:

Merge llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and openmp
8.0.0 final release r356365. There were no functional changes since the
most recent merge, of 8.0.0 rc5.

Release notes for llvm, clang, lld and libc++ 8.0.0 are now available:

https://llvm.org/releases/8.0.0/docs/ReleaseNotes.html
https://llvm.org/releases/8.0.0/tools/clang/docs/ReleaseNotes.html
https://llvm.org/releases/8.0.0/tools/lld/docs/ReleaseNotes.html
https://llvm.org/releases/8.0.0/projects/libcxx/docs/ReleaseNotes.html

PR: 236062

MFC r345349:

Pull in r352826 from upstream lld trunk (by Fangrui Song):

[ELF] Support --{,no-}allow-shlib-undefined

Summary:
In ld.bfd/gold, --no-allow-shlib-undefined is the default when
linking an executable. This patch implements a check to error on
undefined symbols in a shared object, if all of its DT_NEEDED entries
are seen.

Our approach resembles the one used in gold, achieves a good balance
to be useful but not too smart (ld.bfd traces all DSOs and emulates
the behavior of a dynamic linker to catch more cases).

The error is issued based on the symbol table, different from
undefined reference errors issued for relocations. It is most
effective when there are DSOs that were not linked with -z defs (e.g.
when static sanitizers runtime is used).

gold has a comment that some system libraries on GNU/Linux may have
spurious undefined references and thus system libraries should be
excluded (https://sourceware.org/bugzilla/show_bug.cgi?id=6811). The
story may have changed now but we make --allow-shlib-undefined the
default for now. Its interaction with -shared can be discussed in the
future.

Reviewers: ruiu, grimar, pcc, espindola

Reviewed By: ruiu

Subscribers: joerg, emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D57385

Pull in r352943 from upstream lld trunk (by Fangrui Song):

[ELF] Default to --no-allow-shlib-undefined for executables

Summary:
This follows the ld.bfd/gold behavior.

The error check is useful as it captures a common type of ld.so
undefined symbol errors as link-time errors:

// a.cc => a.so (not linked with -z defs)
void f(); // f is undefined
void g() { f(); }

// b.cc => executable with a DT_NEEDED entry on a.so
void g();
int main() { g(); }

// ld.so errors when g() is executed (lazy binding) or when the program is started (-z now)
// symbol lookup error: ... undefined symbol: f

Reviewers: ruiu, grimar, pcc, espindola

Reviewed By: ruiu

Subscribers: llvm-commits, emaste, arichardson

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57569

Together, these add support for --no-allow-shlib-undefined, and make it
the default for executables, so they will fail to link if any symbols
from needed shared libraries are undefined.

Reported by: jbeich
PR: 236062, 236141

MFC r345449:

Pull in r356809 from upstream llvm trunk (by Eli Friedman):

[ARM] Don't form "ands" when it isn't scheduled correctly.

In r322972/r323136, the iteration here was changed to catch cases at
the beginning of a basic block... but we accidentally deleted an
important safety check. Restore that check to the way it was.

Fixes https://bugs.llvm.org/show_bug.cgi?id=41116

Differential Revision: https://reviews.llvm.org/D59680

This should fix "Assertion failed: (LiveCPSR && "CPSR liveness tracking
is wrong!"), function UpdateCPSRUse" errors when building the devel/xwpe
port for armv7.

PR: 236062, 236568

Merge clang 7.0.1 and several follow-up changes

MFC r318594:

Add libc++experimental.a for std::experimental support

This adds a separate library for supporting std::experimental features.
It is purposefully static, and must be explicitly linked into programs
using -lc++experimental.

PLEASE NOTE: there is NO WARRANTY as to any stability or continuing
existence of the features in the std::experimental parts of the C++
library!

Reviewed by: ed
Differential Revision: https://reviews.freebsd.org/D10840

MFC r318598:

Add PICFLAG to build libc++experimental.a, so it can be used in all
situations.

Noticed by: kib

r336969 | emaste | 2018-07-31 16:12:09 +0200 (Tue, 31 Jul 2018) | 13 lines

llvm: [ELF][ARM] Add Arm ABI names for float ABI ELF Header flags

The ELF for the Arm architecture document defines, for EF_ARM_EABI_VER5
and above, the flags EF_ARM_ABI_FLOAT_HARD and EF_ARM_ABI_FLOAT_SOFT.
These have been defined to be compatible with the existing
EF_ARM_VFP_FLOAT and EF_ARM_SOFT_FLOAT used by gcc for
EF_ARM_EABI_UNKNOWN.

This patch adds the flags in addition to the existing ones so that any
code depending on the old names will still work.

Obtained from: llvm r338370 by Peter Smith

r336970 | emaste | 2018-07-31 16:14:41 +0200 (Tue, 31 Jul 2018) | 9 lines

llvm: [ARM] Complete enumeration values for Tag_ABI_VFP_args

The LLD implementation of Tag_ABI_VFP_args needs to check the rarely
seen values of 3 (toolchain specific) and 4 compatible with both Base
and VFP. Add the missing enumeration values so that LLD can refer to
them without having to use the raw numbers.

Obtained from: llvm r338373 by Peter Smith

r336972 | emaste | 2018-07-31 17:25:03 +0200 (Tue, 31 Jul 2018) | 37 lines

lld: [ELF][ARM] Implement support for Tag_ABI_VFP_args

The Tag_ABI_VFP_args build attribute controls the procedure call
standard used for floating point parameters on ARM. The values are:

0 - Base AAPCS (FP Parameters passed in Core (Integer) registers
1 - VFP AAPCS (FP Parameters passed in FP registers)
2 - Toolchain specific (Neither Base or VFP)
3 - Compatible with all (No use of floating point parameters)

If the Tag_ABI_VFP_args build attribute is missing it has an implicit
value of 0.

We use the attribute in two ways:

* Detect a clash in calling convention between Base, VFP and Toolchain.

we follow ld.bfd's lead and do not error if there is a clash between an
implicit Base AAPCS caused by a missing attribute. Many projects
including the hard-float (VFP AAPCS) version of glibc contain assembler
files that do not use floating point but do not have Tag_ABI_VFP_args.

* Set the EF_ARM_ABI_FLOAT_SOFT or EF_ARM_ABI_FLOAT_HARD ELF header flag

for Base or VFP AAPCS respectively. This flag is used by some ELF
loaders.

References:
* Addenda to, and Errata in, the ABI for the ARM Architecture for
Tag_ABI_VFP_args
* Elf for the ARM Architecture for ELF header flags

Fixes LLVM PR36009

PR: 229050
Obtained from: llvm r338377 by Peter Smith

r337282 | alc | 2018-08-04 04:30:51 +0200 (Sat, 04 Aug 2018) | 7 lines

Set the default image base on arm64 and i386 to a superpage-aligned
address.

Reviewed by: emaste, markj
Discussed with: dim
Differential Revision: https://reviews.freebsd.org/D16385

r339304 | emaste | 2018-10-11 15:19:17 +0200 (Thu, 11 Oct 2018) | 13 lines

lld: set sh_link and sh_info for .rela.plt sections

ELF spec says that for SHT_REL and SHT_RELA sh_link should reference the
associated string table and sh_info should reference the "section to
which the relocation applies." ELF Tool Chain's elfcopy / strip use
this (in part) to control whether or not the relocation entry is copied
to the output.

LLVM PR 37538 https://bugs.llvm.org/show_bug.cgi?id=37538

Approved by: re (kib)
Obtained from: llvm r344226 (backported for 6.0)

MFC r341825:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
the upstream release_70 branch r348686 (effectively, 7.0.1 rc3). The
release will follow very soon, but no more functional changes are
expected.

Release notes for llvm, clang and lld 7.0.0 are available here:
<http://releases.llvm.org/7.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/7.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/7.0.0/tools/lld/docs/ReleaseNotes.html>

PR: 230240, 230355
Relnotes: yes

MFC r342123:

Update clang, llvm, lld, lldb, compiler-rt and libc++ version number to
7.0.1 release r349250. There were no functional changes since the 7.0.1
rc3 import.

PR: 230240, 230355
Relnotes: yes

r343429 | emaste | 2019-01-25 15:46:13 +0100 (Fri, 25 Jan 2019) | 16 lines

clang: default to DWARF 4 as of FreeBSD 13

FreeBSD previously defaulted to DWARF 2 because several tools (gdb,
ctfconvert, etc.) did not support later versions. These have either
been fixed or are deprecated.

Note that gdb 6 still exists but has been moved out of $PATH into
/usr/libexec and is intended only for use by crashinfo(8). The kernel
build sets the DWARF version explicitly via -gdwarf2, so this should
have no effect there.

PR: 234887 [exp-run]
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D17930

MFC r343916:

Pull in r352607 from upstream llvm trunk (by Craig Topper):

[X86] Add FPSW as a Def on some FP instructions that were missing it.

Pull in r353141 from upstream llvm trunk (by Craig Topper):

[X86] Connect the default fpsr and dirflag clobbers in inline
assembly to the registers we have defined for them.

Summary:
We don't currently map these constraints to physical register numbers
so they don't make it to the MachineIR representation of inline
assembly.

This could have problems for proper dependency tracking in the
machine schedulers though I don't have a test case that shows that.

Reviewers: rnk

Reviewed By: rnk

Subscribers: eraman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57641

Pull in r353489 from upstream llvm trunk (by Craig Topper):

[X86] Add FPCW as a register and start using it as an implicit use on
floating point instructions.

Summary:
FPCW contains the rounding mode control which we manipulate to
implement fp to integer conversion by changing the roudning mode,
storing the value to the stack, and then changing the rounding mode
back. Because we didn't model FPCW and its dependency chain, other
instructions could be scheduled into the middle of the sequence.

This patch introduces the register and adds it as an implciit def of
FLDCW and implicit use of the FP binary arithmetic instructions and
store instructions. There are more instructions that need to be
updated, but this is a good start. I believe this fixes at least the
reduced test case from PR40529.

Reviewers: RKSimon, spatel, rnk, efriedma, andrew.w.kaylor

Subscribers: dim, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57735

These should fix a problem in clang 7.0 where it would sometimes emit
long double floating point instructions in a slightly wrong order,
leading to failures in our libm tests. In particular, the cbrt_test
test case 'cbrtl_powl' and the trig_test test case 'reduction'.

Also bump __FreeBSD_cc_version, to be able to detect this in our test
suite.

Reported by: lwhsu
PR: 234040
Upstream PR: https://bugs.llvm.org/show_bug.cgi?id=40206

MFC r344056:

Pull in r339734 from upstream llvm trunk (by Eli Friedman):

[ARM] Make PerformSHLSimplify add nodes to the DAG worklist correctly.

Intentionally excluding nodes from the DAGCombine worklist is likely
to lead to weird optimizations and infinite loops, so it's generally
a bad idea.

To avoid the infinite loops, fix DAGCombine to use the
isDesirableToCommuteWithShift target hook before performing the
transforms in question, and implement the target hook in the ARM
backend disable the transforms in question.

Fixes https://bugs.llvm.org/show_bug.cgi?id=38530 . (I don't have a
reduced testcase for that bug. But we should have sufficient test
coverage for PerformSHLSimplify given that we're not playing weird
tricks with the worklist. I can try to bugpoint it if necessary,
though.)

Differential Revision: https://reviews.llvm.org/D50667

This should fix a possible hang when compiling sys/dev/nxge/if_nxge.c
(which exists now only in the stable/11 branch) for arm.

Merge clang, llvm, lld, lldb, compiler-rt and libc++ 6.0.0 release, and
several follow-up fixes.

MFC r327952:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
6.0.0 (branches/release_60 r321788). Upstream has branched for the
6.0.0 release, which should be in about 6 weeks. Please report bugs and
regressions, so we can get them into the release.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

MFC r328010:

Pull in r322473 from upstream llvm trunk (by Andrei Elovikov):

[LV] Don't call recordVectorLoopValueForInductionCast for
newly-created IV from a trunc.

Summary:
This method is supposed to be called for IVs that have casts in their
use-def chains that are completely ignored after vectorization under
PSE. However, for truncates of such IVs the same InductionDescriptor
is used during creation/widening of both original IV based on PHINode
and new IV based on TruncInst.

This leads to unintended second call to
recordVectorLoopValueForInductionCast with a VectorLoopVal set to the
newly created IV for a trunc and causes an assert due to attempt to
store new information for already existing entry in the map. This is
wrong and should not be done.

Fixes PR35773.

Reviewers: dorit, Ayal, mssimpso

Reviewed By: dorit

Subscribers: RKSimon, dim, dcaballe, hsaito, llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D41913

This should fix "Vector value already set for part" assertions when
building the net/iodine and sysutils/daa2iso ports.

Reported by: jbeich
PR: 224867, 224868

MFC r328090:

Pull in r322623 from upstream llvm trunk (by Andrew V. Tischenko):

Allow usage of X86-prefixes as separate instrs.
Differential Revision: https://reviews.llvm.org/D42102

This should fix parse errors when x86 prefixes (such as 'lock' and
'rep') are followed by various non-mnemonic tokens, e.g. comments, .byte
directives and labels.

PR: 224669, 225054

MFC r328091:

Revert r327340, as the workaround for rep prefixes followed by .byte
directives is no longer needed after r328090.

MFC r328141 (by emaste):

lld: Fix for ld.lld does not accept "AT" syntax for declaring LMA region

AT> lma_region expression allows to specify the memory region
for section load address.

Should fix [upstream LLVM] PR35684.

LLVM review: https://reviews.llvm.org/D41397

Obtained from: LLVM r322359 by George Rimar

MFC r328143 (by emaste):

lld: Handle parsing AT(ADDR(.foo-bar)).

The problem we had with it is that anything inside an AT is an
expression, so we failed to parse the section name because of the - in
it.

Requested by: royger
Obtained from: LLVM r322801 by Rafael Espindola

MFC r328144 (by emaste):

lld: Fix incorrect physical address on self-referencing AT command.

When a section placement (AT) command references the section itself,
the physical address of the section in the ELF header was calculated
incorrectly due to alignment happening right after the location
pointer's value was captured.

The problem was diagnosed and the first version of the patch written
by Erick Reyes.

Obtained from: LLVM r322421 by Rafael Espindola

MFC r328145:

Pull in r322016 from upstream llvm trunk (by Sanjay Patel):

[ValueTracking] remove overzealous assert

The test is derived from a failing fuzz test:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5008

Credit to @rksimon for pointing out the problem.

This should fix "Bad flavor while matching min/max" errors when building
the graphics/libsixel and science/kst2 ports.

Reported by: jbeich
PR: 225268, 225269

MFC r328146:

Pull in r322106 from upstream llvm trunk (by Alexey Bataev):

[COST]Fix PR35865: Fix cost model evaluation for shuffle on X86.

Summary:
If the vector type is transformed to non-vector single type, the
compile may crash trying to get vector information about non-vector
type.

Reviewers: RKSimon, spatel, mkuper, hfinkel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D41862

This should fix "Not a vector MVT!" errors when building the
games/dhewm3 port.

Reported by: jbeich
PR: 225271

MFC r328286 (by emaste):

lld: Don't mark a shared library as needed because of a lazy symbol.

Obtained from: LLVM r323221 by Rafael Esp?ndola

MFC r328381:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
6.0.0 (branches/release_60 r323338).

PR: 224669

MFC r328513:

Pull in r322245 from upstream clang trunk (by Craig Topper):

[X86] Make -mavx512f imply -mfma and -mf16c in the frontend like it
does in the backend.

Similarly, make -mno-fma and -mno-f16c imply -mno-avx512f.

Withou this "-mno-sse -mavx512f" ends up with avx512f being enabled
in the frontend but disabled in the backend.

Reported by: pawel
PR: 225488

MFC r328542 (by emaste):

lld: Use lookup instead of find. NFC, just simpler.

Obtained from: LLVM r323395 by Rafael Espindola

MFC r328543 (by emaste):

lld: Only lookup LMARegion once. NFC.

This is similar to how we handle MemRegion.

Obtained from: LLVM r323396 by Rafael Espindola

MFC r328544 (by emaste):

lld: Remove MemRegionOffset. NFC.

We can just use a member variable in MemoryRegion.

Obtained from: LLVM r323399 by Rafael Espindola

MFC r328545 (by emaste):

lld: Simplify. NFC.

Obtained from: LLVM r323440 by Rafael Espindola

MFC r328546 (by emaste):

lld: Improve LMARegion handling.

This fixes the crash reported at [LLVM] PR36083.

The issue is that we were trying to put all the sections in the same
PT_LOAD and crashing trying to write past the end of the file.

This also adds accounting for used space in LMARegion, without it all
3 PT_LOADs would have the same physical address.

Obtained from: LLVM r323449 by Rafael Espindola

MFC r328547 (by emaste):

lld: Move LMAOffset from the OutputSection to the PhdrEntry. NFC.

If two sections are in the same PT_LOAD, their relatives offsets,
virtual address and physical addresses are all the same.

[Rafael] initially wanted to have a single global LMAOffset, on the
assumption that every ELF file was in practiced loaded contiguously in
both physical and virtual memory.

Unfortunately that is not the case. The linux kernel has:

LOAD 0x200000 0xffffffff81000000 0x0000000001000000 0xced000 0xced000 R E 0x200000
LOAD 0x1000000 0xffffffff81e00000 0x0000000001e00000 0x15f000 0x15f000 RW 0x200000
LOAD 0x1200000 0x0000000000000000 0x0000000001f5f000 0x01b198 0x01b198 RW 0x200000
LOAD 0x137b000 0xffffffff81f7b000 0x0000000001f7b000 0x116000 0x1ec000 RWE 0x200000

The delta for all but the third PT_LOAD is the same:
0xffffffff80000000. [Rafael] thinks the 3rd one is a hack for implementing
per cpu data, but we can't break that.

Obtained from: LLVM r323456 by Rafael Espindola

MFC r328548 (by emaste):

lld: Put the header in the first PT_LOAD even if that PT_LOAD has a LMAExpr

The root problem is that we were creating a PT_LOAD just for the header.
That was technically valid, but inconvenient: we should not be making
the ELF discontinuous.

The solution is to allow a section with LMAExpr to be added to a PT_LOAD
if that PT_LOAD doesn't already have a LMAExpr.

LLVM PR: 36017
Obtained from: LLVM r323625 by Rafael Espindola

MFC r328594 (by emaste):

Pull in r322108 from upstream llvm trunk (by Rafael Esp?ndola):

Make one of the emitFill methods non virtual. NFC.

This is just preparatory work to fix [LLVM] PR35858.

MFC r328595 (by emaste):

Pull in r322123 from upstream llvm trunk (by Rafael Esp?ndola):

Don't create MCFillFragment directly.

Instead use higher level APIs that take care of most bookkeeping.

MFC r328596 (by emaste):

Pull in r322131 from upstream llvm trunk (by Rafael Esp?ndola):

Use a MCExpr for the size of MCFillFragment.

This allows the size to be found during ralaxation. This fixes
[LLVM] pr35858.

Requested by: royger

MFC r328753:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
6.0.0 (branches/release_60 r323948).

PR: 224669

MFC r328817:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
6.0.0 (branches/release_60 r324090).

This introduces retpoline support, with the -mretpoline flag. The
upstream initial commit message (r323155 by Chandler Carruth) contains
quite a bit of explanation. Quoting:

Introduce the "retpoline" x86 mitigation technique for variant #2 of
the speculative execution vulnerabilities disclosed today,
specifically identified by CVE-2017-5715, "Branch Target Injection",
and is one of the two halves to Spectre.

Summary:
First, we need to explain the core of the vulnerability. Note that
this is a very incomplete description, please see the Project Zero
blog post for details:
https://googleprojectzero.blogspot.com/2018/01/reading-privileged-memory-with-side.html

The basis for branch target injection is to direct speculative
execution of the processor to some "gadget" of executable code by
poisoning the prediction of indirect branches with the address of
that gadget. The gadget in turn contains an operation that provides a
side channel for reading data. Most commonly, this will look like a
load of secret data followed by a branch on the loaded value and then
a load of some predictable cache line. The attacker then uses timing
of the processors cache to determine which direction the branch took
*in the speculative execution*, and in turn what one bit of the
loaded value was. Due to the nature of these timing side channels and
the branch predictor on Intel processors, this allows an attacker to
leak data only accessible to a privileged domain (like the kernel)
back into an unprivileged domain.

The goal is simple: avoid generating code which contains an indirect
branch that could have its prediction poisoned by an attacker. In
many cases, the compiler can simply use directed conditional branches
and a small search tree. LLVM already has support for lowering
switches in this way and the first step of this patch is to disable
jump-table lowering of switches and introduce a pass to rewrite
explicit indirectbr sequences into a switch over integers.

However, there is no fully general alternative to indirect calls. We
introduce a new construct we call a "retpoline" to implement indirect
calls in a non-speculatable way. It can be thought of loosely as a
trampoline for indirect calls which uses the RET instruction on x86.
Further, we arrange for a specific call->ret sequence which ensures
the processor predicts the return to go to a controlled, known
location. The retpoline then "smashes" the return address pushed onto
the stack by the call with the desired target of the original
indirect call. The result is a predicted return to the next
instruction after a call (which can be used to trap speculative
execution within an infinite loop) and an actual indirect branch to
an arbitrary address.

On 64-bit x86 ABIs, this is especially easily done in the compiler by
using a guaranteed scratch register to pass the target into this
device. For 32-bit ABIs there isn't a guaranteed scratch register
and so several different retpoline variants are introduced to use a
scratch register if one is available in the calling convention and to
otherwise use direct stack push/pop sequences to pass the target
address.

This "retpoline" mitigation is fully described in the following blog
post: https://support.google.com/faqs/answer/7625886

We also support a target feature that disables emission of the
retpoline thunk by the compiler to allow for custom thunks if users
want them. These are particularly useful in environments like
kernels that routinely do hot-patching on boot and want to hot-patch
their thunk to different code sequences. They can write this custom
thunk and use `-mretpoline-external-thunk` *in addition* to
`-mretpoline`. In this case, on x86-64 thu thunk names must be:
```
__llvm_external_retpoline_r11
```
or on 32-bit:
```
__llvm_external_retpoline_eax
__llvm_external_retpoline_ecx
__llvm_external_retpoline_edx
__llvm_external_retpoline_push
```
And the target of the retpoline is passed in the named register, or in
the case of the `push` suffix on the top of the stack via a `pushl`
instruction.

There is one other important source of indirect branches in x86 ELF
binaries: the PLT. These patches also include support for LLD to
generate PLT entries that perform a retpoline-style indirection.

The only other indirect branches remaining that we are aware of are
from precompiled runtimes (such as crt0.o and similar). The ones we
have found are not really attackable, and so we have not focused on
them here, but eventually these runtimes should also be replicated for
retpoline-ed configurations for completeness.

For kernels or other freestanding or fully static executables, the
compiler switch `-mretpoline` is sufficient to fully mitigate this
particular attack. For dynamic executables, you must compile *all*
libraries with `-mretpoline` and additionally link the dynamic
executable and all shared libraries with LLD and pass `-z
retpolineplt` (or use similar functionality from some other linker).
We strongly recommend also using `-z now` as non-lazy binding allows
the retpoline-mitigated PLT to be substantially smaller.

When manually apply similar transformations to `-mretpoline` to the
Linux kernel we observed very small performance hits to applications
running typic al workloads, and relatively minor hits (approximately
2%) even for extremely syscall-heavy applications. This is largely
due to the small number of indirect branches that occur in
performance sensitive paths of the kernel.

When using these patches on statically linked applications,
especially C++ applications, you should expect to see a much more
dramatic performance hit. For microbenchmarks that are switch,
indirect-, or virtual-call heavy we have seen overheads ranging from
10% to 50%.

However, real-world workloads exhibit substantially lower performance
impact. Notably, techniques such as PGO and ThinLTO dramatically
reduce the impact of hot indirect calls (by speculatively promoting
them to direct calls) and allow optimized search trees to be used to
lower switches. If you need to deploy these techniques in C++
applications, we *strongly* recommend that you ensure all hot call
targets are statically linked (avoiding PLT indirection) and use both
PGO and ThinLTO. Well tuned servers using all of these techniques saw
5% - 10% overhead from the use of retpoline.

We will add detailed documentation covering these components in
subsequent patches, but wanted to make the core functionality
available as soon as possible. Happy for more code review, but we'd
really like to get these patches landed and backported ASAP for
obvious reasons. We're planning to backport this to both 6.0 and 5.0
release streams and get a 5.0 release with just this cherry picked
ASAP for distros and vendors.

This patch is the work of a number of people over the past month:
Eric, Reid, Rui, and myself. I'm mailing it out as a single commit
due to the time sensitive nature of landing this and the need to
backport it. Huge thanks to everyone who helped out here, and
everyone at Intel who helped out in discussions about how to craft
this. Also, credit goes to Paul Turner (at Google, but not an LLVM
contributor) for much of the underlying retpoline design.

Reviewers: echristo, rnk, ruiu, craig.topper, DavidKreitzer

Subscribers: sanjoy, emaste, mcrosier, mgorny, mehdi_amini, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D41723

PR: 224669

MFC r329033:

Pull in r324594 from upstream clang trunk (by Alexander Ivchenko):

Fix for #31362 - ms_abi is implemented incorrectly for values >=16
bytes.

Summary:
This patch is a fix for following issue:
https://bugs.llvm.org/show_bug.cgi?id=31362 The problem was caused by
front end lowering C calling conventions without taking into account
calling conventions enforced by attribute. In this case win64cc was
no correctly lowered on targets other than Windows.

Reviewed By: rnk (Reid Kleckner)

Differential Revision: https://reviews.llvm.org/D43016

Author: belickim <mateusz.belicki@intel.com>

This fixes clang 6.0.0 assertions when building the emulators/wine and
emulators/wine-devel ports, and should also make it use the correct
Windows calling conventions. Bump __FreeBSD_version to make the fix
easy to detect.

PR: 224863

MFC r329223:

Pull in r323998 from upstream clang trunk (by Richard Smith):

PR36157: When injecting an implicit function declaration in C89, find
the right DeclContext rather than injecting it wherever we happen to
be.

This avoids creating functions whose DeclContext is a struct or
similar.

This fixes assertion failures when parsing certain not-completely-valid
struct declarations.

Reported by: ae
PR: 225862

MFC r329410:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
6.0.0 (branches/release_60 r325330).

PR: 224669

MFC r329983:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
6.0.0 (branches/release_60 r325932). This corresponds to 6.0.0 rc3.

PR: 224669

MFC r330384:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
6.0.0 release (upstream r326565).

Release notes for llvm, clang and lld will be available here soon:
<http://releases.llvm.org/6.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/6.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/6.0.0/tools/lld/docs/ReleaseNotes.html>

Relnotes: yes
PR: 224669

MFC r330686:

Pull in r326882 from upstream llvm trunk (by Sjoerd Meijer):

[ARM] Fix for PR36577

Don't PerformSHLSimplify if the given node is used by a node that
also uses a constant because we may get stuck in an infinite combine
loop.

bugzilla: https://bugs.llvm.org/show_bug.cgi?id=36577

Patch by Sam Parker.

Differential Revision: https://reviews.llvm.org/D44097

This fixes a hang when compiling one particular file in java/openjdk8
for armv6 and armv7.

Reported by: swills
PR: 226388

MFC r331065:

Pull in r327638 from upstream llvm trunk (by Matthew Simpson):

[ConstantFolding, InstSimplify] Handle more vector GEPs

This patch addresses some additional cases where the compiler crashes
upon encountering vector GEPs. This should fix PR36116.

Differential Revision: https://reviews.llvm.org/D44219
Reference: https://bugs.llvm.org/show_bug.cgi?id=36116

This fixes an assertion when building the emulators/snes9x port.

Reported by: jbeich
PR: 225471

MFC r331066:

Pull in r321999 from upstream clang trunk (by Ivan A. Kosarev):

[CodeGen] Fix TBAA info for accesses to members of base classes

Resolves:
Bug 35724 - regression (r315984): fatal error: error in backend:
Broken function found (Did not see access type in access path!)
https://bugs.llvm.org/show_bug.cgi?id=35724

Differential Revision: https://reviews.llvm.org/D41547

This fixes "Did not see access type in access path" fatal errors when
building the devel/gdb port (version 8.1).

Reported by: jbeich
PR: 226658

MFC r331366:

Pull in r327101 from upstream llvm trunk (by Rafael Espindola):

Don't treat .symver as a regular alias definition.

This patch starts simplifying the handling of .symver.

For now it just moves the responsibility for creating an alias down to
the streamer. With that the asm streamer can pass a .symver unchanged,
which is nice since gas cannot parse "foo@bar = zed".

In a followup I hope to move the handling down to the writer so that
we don't need special hacks for avoiding breaking names with @@@ on
windows.

Pull in r327160 from upstream llvm trunk (by Rafael Espindola):

Delay creating an alias for @@@.

With this we only create an alias for @@@ once we know if it should
use @ or @@. This avoids last minutes renames and hacks to handle MS
names.

This only handles the ELF writer. LTO still has issues with @@@
aliases.

Pull in r327928 from upstream llvm trunk (by Vitaly Buka):

Object: Move attribute calculation into RecordStreamer. NFC

Summary: Preparation for D44274

Reviewers: pcc, espindola

Subscribers: hiraditya

Differential Revision: https://reviews.llvm.org/D44276

Pull in r327930 from upstream llvm trunk (by Vitaly Buka):

Object: Fix handling of @@@ in .symver directive

Summary:
name@@@nodename is going to be replaced with name@@nodename if symbols is
defined in the assembled file, or name@nodename if undefined.
https://sourceware.org/binutils/docs/as/Symver.html

Fixes PR36623

Reviewers: pcc, espindola

Subscribers: mehdi_amini, hiraditya

Differential Revision: https://reviews.llvm.org/D44274

Together, these changes fix handling of @@@ in .symver directives when
doing Link Time Optimization.

Reported by: Shawn Webb <shawn.webb@hardenedbsd.org>

MFC r331731:

Pull in r328738 from upstream lld trunk (by Rafael Espindola):

Strip @VER suffices from the LTO output.

This fixes pr36623.

The problem is that we have to parse versions out of names before LTO
so that LTO can use that information.

When we get the LTO produced .o files, we replace the previous symbols
with the LTO produced ones, but they still have @ in their names.

We could just trim the name directly, but calling parseSymbolVersion
to do it is simpler.

This is a follow-up to r331366, since we discovered that lld could
append version strings to symbols twice, when using Link Time
Optimization.

Merge clang, llvm, lld, lldb, compiler-rt and libc++ 5.0.0 release.

MFC r309126 (by emaste):

Correct lld llvm-tblgen dependency file name

MFC r309169:

Get rid of separate Subversion mergeinfo properties for llvm-dwarfdump
and llvm-lto. The mergeinfo confuses Subversion enormously, and these
directories will just use the mergeinfo for llvm itself.

MFC r312765:

Pull in r276136 from upstream llvm trunk (by Wei Mi):

Use ValueOffsetPair to enhance value reuse during SCEV expansion.

In D12090, the ExprValueMap was added to reuse existing value during
SCEV expansion. However, const folding and sext/zext distribution can
make the reuse still difficult.

A simplified case is: suppose we know S1 expands to V1 in
ExprValueMap, and
S1 = S2 + C_a
S3 = S2 + C_b
where C_a and C_b are different SCEVConstants. Then we'd like to
expand S3 as V1 - C_a + C_b instead of expanding S2 literally. It is
helpful when S2 is a complex SCEV expr and S2 has no entry in
ExprValueMap, which is usually caused by the fact that S3 is
generated from S1 after const folding.

In order to do that, we represent ExprValueMap as a mapping from SCEV
to ValueOffsetPair. We will save both S1->{V1, 0} and S2->{V1, C_a}
into the ExprValueMap when we create SCEV for V1. When S3 is
expanded, it will first expand S2 to V1 - C_a because of S2->{V1,
C_a} in the map, then expand S3 to V1 - C_a + C_b.

Differential Revision: https://reviews.llvm.org/D21313

This should fix assertion failures when building OpenCV >= 3.1.

PR: 215649

MFC r312831:

Revert r312765 for now, since it causes assertions when building
lang/spidermonkey24.

Reported by: antoine
PR: 215649

MFC r316511 (by jhb):

Add an implementation of __ffssi2() derived from __ffsdi2().

Newer versions of GCC include an __ffssi2() symbol in libgcc and the
compiler can emit calls to it in generated code. This is true for at
least GCC 6.2 when compiling world for mips and mips64.

Reviewed by: jmallett, dim
Sponsored by: DARPA / AFRL
Differential Revision: https://reviews.freebsd.org/D10086

MFC r318601 (by adrian):

[libcompiler-rt] add bswapdi2/bswapsi2

This is required for mips gcc 6.3 userland to build/run.

Reviewed by: emaste, dim
Approved by: emaste
Differential Revision: https://reviews.freebsd.org/D10838

MFC r318884 (by emaste):

lldb: map TRAP_CAP to a trace trap

In the absense of a more specific handler for TRAP_CAP (generated by
ENOTCAPABLE or ECAPMODE while in capability mode) treat it as a trace
trap.

Example usage (testing the bug in PR219173):

% proccontrol -m trapcap lldb usr.bin/hexdump/obj/hexdump -- -Cv -s 1 /bin/ls
...
(lldb) run
Process 12980 launching
Process 12980 launched: '.../usr.bin/hexdump/obj/hexdump' (x86_64)
Process 12980 stopped
* thread #1, stop reason = trace
frame #0: 0x0000004b80c65f1a libc.so.7`__sys_lseek + 10
...

In the future we should have LLDB control the trapcap procctl itself
(as it does with ASLR), as well as report a specific stop reason.
This change eliminates an assertion failure from LLDB for now.

MFC r319796:

Remove a few unneeded files from libllvm, libclang and liblldb.

MFC r319885 (by emaste):

lld: ELF: Fix ICF crash on absolute symbol relocations.

If two sections contained relocations to absolute symbols with the same
value we would crash when trying to access their sections. Add a check that
both symbols point to sections before accessing their sections, and treat
absolute symbols as equal if their values are equal.

Obtained from: LLD commit r292578

MFC r319918:

Revert r319796 for now, it can cause undefined references when linking
in some circumstances.

Reported by: Shawn Webb <shawn.webb@hardenedbsd.org>

MFC r319957 (by emaste):

lld: Add armelf emulation mode

Obtained from: LLD r305375

MFC r321369:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
5.0.0 (trunk r308421). Upstream has branched for the 5.0.0 release,
which should be in about a month. Please report bugs and regressions,
so we can get them into the release.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

MFC r321420:

Add a few more object files to liblldb, which should solve errors when
linking the lldb executable in some cases. In particular, when the
-ffunction-sections -fdata-sections options are turned off, or
ineffective.

Reported by: Shawn Webb, Mark Millard

MFC r321433:

Cleanup stale Options.inc files from the previous libllvm build for
clang 4.0.0. Otherwise, these can get included before the two newly
generated ones (which are different) for clang 5.0.0.

Reported by: Mark Millard

MFC r321439 (by bdrewery):

Move llvm Options.inc hack from r321433 for NO_CLEAN to lib/clang/libllvm.

The files are only ever generated to .OBJDIR, not to WORLDTMP (as a
sysroot) and are only ever included from a compilation. So using
a beforebuild target here removes the file before the compilation
tries to include it.

MFC r321664:

Pull in r308891 from upstream llvm trunk (by Benjamin Kramer):

[CodeGenPrepare] Cut off FindAllMemoryUses if there are too many uses.

This avoids excessive compile time. The case I'm looking at is
Function.cpp from an old version of LLVM that still had the giant
memcmp string matcher in it. Before r308322 this compiled in about 2
minutes, after it, clang takes infinite* time to compile it. With
this patch we're at 5 min, which is still bad but this is a
pathological case.

The cut off at 20 uses was chosen by looking at other cut-offs in LLVM
for user scanning. It's probably too high, but does the job and is
very unlikely to regress anything.

Fixes PR33900.

* I'm impatient and aborted after 15 minutes, on the bug report it was
killed after 2h.

Pull in r308986 from upstream llvm trunk (by Simon Pilgrim):

[X86][CGP] Reduce memcmp() expansion to 2 load pairs (PR33914)

D35067/rL308322 attempted to support up to 4 load pairs for memcmp
inlining which resulted in regressions for some optimized libc memcmp
implementations (PR33914).

Until we can match these more optimal cases, this patch reduces the
memcmp expansion to a maximum of 2 load pairs (which matches what we
do for -Os).

This patch should be considered for the 5.0.0 release branch as well

Differential Revision: https://reviews.llvm.org/D35830

These fix a hang (or extremely long compile time) when building older
LLVM ports.

Reported by: antoine
PR: 219139

MFC r321719:

Pull in r309503 from upstream clang trunk (by Richard Smith):

PR33902: Invalidate line number cache when adding more text to
existing buffer.

This led to crashes as the line number cache would report a bogus
line number for a line of code, and we'd try to find a nonexistent
column within the line when printing diagnostics.

This fixes an assertion when building the graphics/champlain port.

Reported by: antoine, kwm
PR: 219139

MFC r321723:

Upgrade our copies of clang, llvm, lld and lldb to r309439 from the
upstream release_50 branch. This is just after upstream's 5.0.0-rc1.

MFC r322320:

Upgrade our copies of clang, llvm and libc++ to r310316 from the
upstream release_50 branch.

MFC r322326 (by emaste):

lldb: Make i386-*-freebsd expression work on JIT path

* Enable i386 ABI creation for freebsd
* Added an extra argument in ABISysV_i386::PrepareTrivialCall for mmap
syscall
* Unlike linux, the last argument of mmap is actually 64-bit(off_t).
This requires us to push an additional word for the higher order bits.
* Prior to this change, ktrace dump will show mmap failures due to
invalid argument coming from the 6th mmap argument.

Submitted by: Karnajit Wangkhem
Differential Revision: https://reviews.llvm.org/D34776

MFC r322360 (by emaste):

lldb: Report inferior signals as signals, not exceptions, on FreeBSD

This is the FreeBSD equivalent of LLVM r238549.

This serves 2 purposes:

* LLDB should handle inferior process signals SIGSEGV/SIGILL/SIGBUS/
SIGFPE the way it is suppose to be handled. Prior to this fix these
signals will neither create a coredump, nor exit from the debugger
or work for signal handling scenario.
* eInvalidCrashReason need not report "unknown crash reason" if we have
a valid si_signo

llvm.org/pr23699

Patch by Karnajit Wangkhem

Differential Revision: https://reviews.llvm.org/D35223

Submitted by: Karnajit Wangkhem
Obtained from: LLVM r310591

MFC r322474 (by emaste):

lld: Add `-z muldefs` option.

Obtained from: LLVM r310757

MFC r322740:

Upgrade our copies of clang, llvm, lld and libc++ to r311219 from the
upstream release_50 branch.

MFC r322855:

Upgrade our copies of clang, llvm, lldb and compiler-rt to r311606 from
the upstream release_50 branch.

As of this version, lib/msun's trig test should also work correctly
again (see bug 220989 for more information).

PR: 220989

MFC r323112:

Upgrade our copies of clang, llvm, lldb and compiler-rt to r312293 from
the upstream release_50 branch. This corresponds to 5.0.0 rc4.

As of this version, the cad/stepcode port should now compile in a more
reasonable time on i386 (see bug 221836 for more information).

PR: 221836

MFC r323245:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
5.0.0 release (upstream r312559).

Release notes for llvm, clang and lld will be available here soon:
<http://releases.llvm.org/5.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/5.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/5.0.0/tools/lld/docs/ReleaseNotes.html>

Relnotes: yes

Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release:

MFC r309142 (by emaste):

Add WITH_LLD_AS_LD build knob

If set it installs LLD as /usr/bin/ld. LLD (as of version 3.9) is not
capable of linking the world and kernel, but can self-host and link many
substantial applications. GNU ld continues to be used for the world and
kernel build, regardless of how this knob is set.

It is on by default for arm64, and off for all other CPU architectures.

Sponsored by: The FreeBSD Foundation

MFC r310840:

Reapply 310775, now it also builds correctly if lldb is disabled:

Move llvm-objdump from CLANG_EXTRAS to installed by default

We currently install three tools from binutils 2.17.50: as, ld, and
objdump. Work is underway to migrate to a permissively-licensed
tool-chain, with one goal being the retirement of binutils 2.17.50.

LLVM's llvm-objdump is intended to be compatible with GNU objdump
although it is currently missing some options and may have formatting
differences. Enable it by default for testing and further investigation.
It may later be changed to install as /usr/bin/objdump, it becomes a
fully viable replacement.

Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D8879

MFC r312855 (by emaste):

Rename LLD_AS_LD to LLD_IS_LD, for consistency with CLANG_IS_CC

Reported by: Dan McGregor <dan.mcgregor usask.ca>

MFC r313559 | glebius | 2017-02-10 18:34:48 +0100 (Fri, 10 Feb 2017) | 5 lines

Don't check struct rtentry on FreeBSD, it is an internal kernel structure.
On other systems it may be API structure for SIOCADDRT/SIOCDELRT.

Reviewed by: emaste, dim

MFC r314152 (by jkim):

Remove an assembler flag, which is redundant since r309124. The upstream
took care of it by introducing a macro NO_EXEC_STACK_DIRECTIVE.

http://llvm.org/viewvc/llvm-project?rev=273500&view=rev

Reviewed by: dim

MFC r314564:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
4.0.0 (branches/release_40 296509). The release will follow soon.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Also note that as of 4.0.0, lld should be able to link the base system
on amd64 and aarch64. See the WITH_LLD_IS_LLD setting in src.conf(5).
Though please be aware that this is work in progress.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/4.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Jan Beich, Antoine Brodin and Eric Fiselier for
their help.

Relnotes: yes
Exp-run: antoine
PR: 215969, 216008

MFC r314708:

For now, revert r287232 from upstream llvm trunk (by Daniil Fukalov):

[SCEV] limit recursion depth of CompareSCEVComplexity

Summary:
CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
loop) and runs almost infinite time.

Added cache of "equal" SCEV pairs to earlier cutoff of further
estimation. Recursion depth limit was also introduced as a parameter.

Reviewers: sanjoy

Subscribers: mzolotukhin, tstellarAMD, llvm-commits

Differential Revision: https://reviews.llvm.org/D26389

This commit is the cause of excessive compile times on skein_block.c
(and possibly other files) during kernel builds on amd64.

We never saw the problematic behavior described in this upstream commit,
so for now it is better to revert it. An upstream bug has been filed
here: https://bugs.llvm.org/show_bug.cgi?id=32142

Reported by: mjg

MFC r314795:

Reapply r287232 from upstream llvm trunk (by Daniil Fukalov):

[SCEV] limit recursion depth of CompareSCEVComplexity

Summary:
CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
loop) and runs almost infinite time.

Added cache of "equal" SCEV pairs to earlier cutoff of further
estimation. Recursion depth limit was also introduced as a parameter.

Reviewers: sanjoy

Subscribers: mzolotukhin, tstellarAMD, llvm-commits

Differential Revision: https://reviews.llvm.org/D26389

Pull in r296992 from upstream llvm trunk (by Sanjoy Das):

[SCEV] Decrease the recursion threshold for CompareValueComplexity

Fixes PR32142.

r287232 accidentally increased the recursion threshold for
CompareValueComplexity from 2 to 32. This change reverses that
change by introducing a separate flag for CompareValueComplexity's
threshold.

The latter revision fixes the excessive compile times for skein_block.c.

MFC r314907 | mmel | 2017-03-08 12:40:27 +0100 (Wed, 08 Mar 2017) | 7 lines

Unbreak ARMv6 world.

The new compiler_rt library imported with clang 4.0.0 have several fatal
issues (non-functional __udivsi3 for example) with ARM specific instrict
functions. As temporary workaround, until upstream solve these problems,
disable all thumb[1][2] related feature.

MFC r315016:

Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release.
We were already very close to the last release candidate, so this is a
pretty minor update.

Relnotes: yes

MFC r316005:

Revert r314907, and pull in r298713 from upstream compiler-rt trunk (by
Weiming Zhao):

builtins: Select correct code fragments when compiling for Thumb1/Thum2/ARM ISA.

Summary:
Value of __ARM_ARCH_ISA_THUMB isn't based on the actual compilation
mode (-mthumb, -marm), it reflect's capability of given CPU.

Due to this:
- use __tbumb__ and __thumb2__ insteand of __ARM_ARCH_ISA_THUMB
- use '.thumb' directive consistently in all affected files
- decorate all thumb functions using
DEFINE_COMPILERRT_THUMB_FUNCTION()

---------
Note: This patch doesn't fix broken Thumb1 variant of __udivsi3 !

Reviewers: weimingz, rengolin, compnerd

Subscribers: aemerson, dim

Differential Revision: https://reviews.llvm.org/D30938

Discussed with: mmel

MFC r309124:

Upgrade our copies of clang, llvm, lldb, compiler-rt and libc++ to 3.9.0
release, and add lld 3.9.0. Also completely revamp the build system for
clang, llvm, lldb and their related tools.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Release notes for llvm, clang and lld are available here:
<http://llvm.org/releases/3.9.0/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/clang/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Bryan Drewery, Andrew Turner, Antoine Brodin and Jan
Beich for their help.

Relnotes: yes

MFC r309147:

Pull in r282174 from upstream llvm trunk (by Krzysztof Parzyszek):

[PPC] Set SP after loading data from stack frame, if no red zone is
present

Follow-up to r280705: Make sure that the SP is only restored after
all data is loaded from the stack frame, if there is no red zone.

This completes the fix for
https://llvm.org/bugs/show_bug.cgi?id=26519.

Differential Revision: https://reviews.llvm.org/D24466

Reported by: Mark Millard
PR: 214433

MFC r309149:

Pull in r283060 from upstream llvm trunk (by Hal Finkel):

[PowerPC] Refactor soft-float support, and enable PPC64 soft float

This change enables soft-float for PowerPC64, and also makes
soft-float disable all vector instruction sets for both 32-bit and
64-bit modes. This latter part is necessary because the PPC backend
canonicalizes many Altivec vector types to floating-point types, and
so soft-float breaks scalarization support for many operations. Both
for embedded targets and for operating-system kernels desiring
soft-float support, it seems reasonable that disabling hardware
floating-point also disables vector instructions (embedded targets
without hardware floating point support are unlikely to have Altivec,
etc. and operating system kernels desiring not to use floating-point
registers to lower syscall cost are unlikely to want to use vector
registers either). If someone needs this to work, we'll need to
change the fact that we promote many Altivec operations to act on
v4f32. To make it possible to disable Altivec when soft-float is
enabled, hardware floating-point support needs to be expressed as a
positive feature, like the others, and not a negative feature,
because target features cannot have dependencies on the disabling of
some other feature. So +soft-float has now become -hard-float.

Fixes PR26970.

Pull in r283061 from upstream clang trunk (by Hal Finkel):

[PowerPC] Enable soft-float for PPC64, and +soft-float -> -hard-float

Enable soft-float support on PPC64, as the backend now supports it.
Also, the backend now uses -hard-float instead of +soft-float, so set
the target features accordingly.

Fixes PR26970.

Reported by: Mark Millard
PR: 214433

MFC r309212:

Add a few missed clang 3.9.0 files to OptionalObsoleteFiles.

MFC r309262:

Fix packaging for clang, lldb and lld 3.9.0

During the upgrade of clang/llvm etc to 3.9.0 in r309124, the PACKAGE
directive in the usr.bin/clang/*.mk files got dropped accidentally.

Restore it, with a few minor changes and additions:
* Correct license in clang.ucl to NCSA
* Add PACKAGE=clang for clang and most of the "ll" tools
* Put lldb in its own package
* Put lld in its own package

Reviewed by: gjb, jmallett
Differential Revision: https://reviews.freebsd.org/D8666

MFC r309656:

During the bootstrap phase, when building the minimal llvm library on
PowerPC, add lib/Support/Atomic.cpp. This is needed because upstream
llvm revision r271821 disabled the use of std::call_once, which causes
some fallback functions from Atomic.cpp to be used instead.

Reported by: Mark Millard
PR: 214902

MFC r309835:

Tentatively apply https://reviews.llvm.org/D18730 to work around gcc PR
70528 (bogus error: constructor required before non-static data member).
This should fix buildworld with the external gcc package.

Reported by: https://jenkins.freebsd.org/job/FreeBSD_HEAD_amd64_gcc/

MFC r310194:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
3.9.1 release.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/3.9.1/docs/ReleaseNotes.html>
<http://releases.llvm.org/3.9.1/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/3.9.1/tools/lld/docs/ReleaseNotes.html>

Relnotes: yes

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Implement (ACFLAGS|CFLAGS|CXXFLAGS).SRC globally.

Sponsored by: EMC / Isilon Storage Division

Upgrade our copies of clang, llvm, lldb and compiler-rt to 3.8.0
release.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Release notes for llvm and clang will soon be available here:
<http://llvm.org/releases/3.8.0/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.8.0/tools/clang/docs/ReleaseNotes.html>

Thanks to Ed Maste, Roman Divacky, Davide Italiano and Antoine Brodin
for their help.

Relnotes: yes

Merge compiler-rt release_38 branch r258968.

Note that there is still a problem on amd64, causing SIGBUS in the early
startup of Address Sanitizer. This is being investigated.